Segment Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011
Industry segment and foreign operations
Number of reportable business segments									2
Financial results of reportable segments
Sales	$ 103,102,000	$ 79,783,000	$ 79,355,000	$ 67,219,000	$ 90,560,000	$ 82,883,000	$ 86,320,000	$ 74,650,000	$ 329,459,000	$ 334,413,000	$ 341,573,000
Depreciation and amortization									9,560,000	7,451,000	7,736,000
Segment income					6,545,000	5,311,000	4,838,000	3,388,000	6,996,000	20,082,000	16,597,000
Capital expenditures									3,871,000	7,641,000	19,217,000
Segment assets	343,968,000				325,654,000				343,968,000	325,654,000
Reconciliation of segment income to consolidated income before income taxes
Unallocated corporate expense									(3,075,000)	(5,419,000)	(4,619,000)
Acquisition related inventory step-up charge									(1,927,000)
Acquisition related expenses									(2,154,000)	(290,000)
Impairment charges									6,239,000
Interest expense, net									(1,064,000)	(741,000)	(238,000)
Other unallocated expense									(148,000)	(145,000)	69,000
Income from continuing operations before income taxes									5,932,000	19,341,000	16,359,000
Reconciliation of segment assets to consolidated total assets
Total assets	343,968,000				325,654,000				343,968,000	325,654,000
MMS | High volume products
Industry segment and foreign operations
Minimum sales price									60,000
MMS | Lower volume grinding machines
Industry segment and foreign operations
Maximum sales price									1,500,000
ATA
Industry segment and foreign operations
Number of primary product groups									2
ATA | High volume collets
Industry segment and foreign operations
Minimum sales price									50
ATA | Specialty chucks
Industry segment and foreign operations
Maximum sales price									20,000
Operating segment
Financial results of reportable segments
Sales									329,459,000	334,413,000	341,573,000
Depreciation and amortization									8,882,000	6,747,000	6,838,000
Segment income									20,539,000	25,936,000	21,147,000
Capital expenditures									3,867,000	16,368,000	19,217,000
Segment assets	303,208,000				294,209,000				303,208,000	294,209,000	285,682,000
Reconciliation of segment assets to consolidated total assets
Total assets	303,208,000				294,209,000				303,208,000	294,209,000	285,682,000
Operating segment | MMS
Financial results of reportable segments
Sales									278,377,000	306,328,000	316,062,000
Depreciation and amortization									6,897,000	6,041,000	6,088,000
Segment income									14,850,000	20,808,000	16,904,000
Capital expenditures									2,376,000	15,732,000	18,886,000
Segment assets	249,999,000				275,894,000				249,999,000	275,894,000	266,983,000
Reconciliation of segment assets to consolidated total assets
Total assets	249,999,000				275,894,000				249,999,000	275,894,000	266,983,000
Operating segment | ATA
Financial results of reportable segments
Sales									51,553,000	28,989,000	27,055,000
Depreciation and amortization									1,985,000	706,000	750,000
Segment income									5,689,000	5,128,000	4,243,000
Capital expenditures									1,491,000	636,000	331,000
Segment assets	53,209,000				18,315,000				53,209,000	18,315,000	18,699,000
Reconciliation of segment assets to consolidated total assets
Total assets	53,209,000				18,315,000				53,209,000	18,315,000	18,699,000
Inter segment eliminations
Financial results of reportable segments
Sales									(471,000)	(904,000)	(1,544,000)
Unallocated assets
Financial results of reportable segments
Segment assets	40,760,000				31,445,000				40,760,000	31,445,000
Reconciliation of segment assets to consolidated total assets
Total assets	40,760,000				31,445,000				40,760,000	31,445,000
Cash	$ 34,700,000				$ 26,900,000				$ 34,700,000	$ 26,900,000	$ 21,700,000
Previously Reported
Industry segment and foreign operations
Number of reportable business segments									1